Research examining the costs of disability transitions of individuals 65 years of age and older has previously been published: Hoffman JM, Ciol MA, Huynh M, Chan L: Estimating transition probabilities in mobility and total costs for Medicare beneficiaries. Arch Phys Med Rehabil 2010; 91(12):1849-55 In 2014, research examining transitions in ADLs, IADLs, and mobility among working-age Medicare beneficiaries was published in the Disability and Health Journal. This research examined characteristics of Medicare beneficiaries under age 65 who receive benefits for reasons other than end stage renal disease. Descriptive statistics reveal at the time of the first interview, the five most cited primary reasons for Medicare eligibility were mental disorder (21%), mental retardation (13%), back/spine/disc problems (9%), rheumatoid or other type of arthritis (7%), and stroke (4%), with 16% reporting a non-specific primary reason for eligibility. At least three co-morbid conditions were reported by 49% of the sample at baseline, with mental disorders, hypertension, and arthritis most commonly cited (47%, 42%, and 41%). We found that, from the standpoint of function, the working-age Medicare population with disability is fairly stable from one year to the next. Whether the disability metric is mobility, ADLs or IADLs, 75%-90% of our sample either did not report any disability or their level of disability did not change from one year to the next. However, we also found that there was a substantial proportion of the cohort that reported functional improvement or decline over the short timeframe of the MCBS. Depending on the condition and disability metric, as many as 13-14% of individuals with certain conditions showed change in their functional status. The dynamic nature of disability has important implications for social policies related to disability. This study showed that, in the working age population with disability, a small percentage of individuals will improve or worsen from one year to the next. These transitions are associated with variety of individual characteristics including age, weight, co-morbid illnesses, and primary diagnosis. Further research applied to larger samples is required to refine policy relevant models that might inform decisions related to ongoing eligibility for national disability programs. Publications generated by this year's research: Ciol MA, Rasch EK, Hoffman J, Huynh M, Chan L: Transitions in Mobility, ADLs, and IADLs among working-age Medicare beneficiaries. Disability and Health Journal 2014; 7(2):206215 The data use agreement between University of Washington and CMS (DUA 19622) expired on 8/29/2014. CMS was sent written certification of data disposition. No further work is planned on this protocol.